The present invention relates generally to systems that employ oscillating components, and more particularly, to a system that provides an integrated solution to bearing life and torque compensation problems in systems having oscillating components.
In the application of mechanical elements subjected to oscillatory rotary motion, the variation of speed due to slow down, stopping and reversing of the direction of rotation, causes two undesirable results. The first is the interruption of the lubrication film between the bearing rolling stock (balls, rollers) and the bearing races, which degrades the life of the bearings. The second is the creation of a reaction torque that disturbs the supporting structure.
The interruption of motion at the end of each oscillation due to stopping and reversing actions creates a temporary dry condition in the bearings due to the interruption of hydrodynamic flow of lubricant. This temporary dry condition produces high friction and contact stresses that considerably shorten the life of the bearing.
Traditional designs use lubrication systems where oil is pumped or fed by gravity to submerge balls of the bearings in oil and prevent dry running. This type of system produces high friction and is very susceptible to oil migration and leaks.
Traditionally, reaction torque compensation is done using a mass that produces an inertial that matches the inertia of a primary payload. The mass is moved an equal amount but in the opposite direction from the primary payload to cancel the disturbance torque. Since this is accomplished using a system that also operates in oscillatory motion, it subjects the bearings supporting the reaction mass to oscillatory motion. The end result is that two sets of bearings operate in a very unfavorable environment with regard to bearing life.
It would therefore be desirable to have a system that provides an integrated solution to bearing life and torque compensation problems in systems having oscillating components.